What Is Visceral Leishmaniasis?

Leishmaniasis is a zoonotic disease caused by Leishmania and can cause black fever in human skin and internal organs. The clinical features are mainly long-term irregular fever, splenomegaly, anemia, weight loss, decreased white blood cell count, and increased serum globulin. Without proper treatment, most patients will be complicated by other diseases within 1 to 2 years after the illness. death. The disease occurs frequently in Mediterranean countries and in tropical and subtropical regions, with skin leishmaniasis the most common form.

Basic Information

English name: leishmaniasis
Visiting department: Infectious Diseases
Multiple groups: People on a hill or loess plateau

Common causes: Leishmania infection
Common symptoms: Long-term irregular fever, splenomegaly, anemia, weight loss, etc.
Contagious: Have
way for spreading: Amaranth, mammals and reptiles, etc.

Causes of Leishmaniasis

Leishmania and Trypanosoma belong to the same family, Trypanosoma. Currently, up to 16 species or subspecies of pathogenic Leishmania have been reported. Leishmania exhibits different forms with different stages of life history. According to the common characteristics of their life history, there are two periods of pre-flagellate body and aflagellate body. The pre-flagellate body is parasitic in the digestive tract of invertebrates, and its host is white pheasant. Amastiform bodies are parasitic in the reticuloendothelial cells of vertebrates, and their hosts are mammals and reptiles.

The anterior flagella is round or oval, without free flagella. There is a large circular nucleus and rod-shaped moving substrate in the worm body, and occasional vacuoles can be seen between the moving substrate and the nucleus. The pre-flagellate body is narrow and long, with a size of 15-20 × 1.5-3.5 m. The moving matrix is at the front of the nucleus, and a flagella is extended as a moving organ. The amastiform body is oval or round, and the worm body is oval, and the size is 1.5 3 × 2.5 6.5m. Amastigotes are more commonly found in macrophages of infected animals, but on smears, they are often released outside the cell due to rupture of macrophages, and can sometimes be scattered on red blood cells.

Leishmaniasis epidemiology

Visceral Leishmaniasis or Black Fever pathogens are stored in domestic dogs. It is then transmitted from dogs to humans and becomes an infectious disease transmitted by humans and beasts. In areas where canine visceral leishmaniasis or canine black fever is prevalent abroad, it is closely related to the spread of local human black fever. Leishmaniasis is transmitted by blood-sucking insects of the genus Astragalus (Eastern Hemisphere) and the genus Rhizoma (Western Hemisphere).

The epidemic of this disease is closely related to climate and environment. For example, in some parts of Asia, the Middle East, the Mediterranean Basin, and South America, Leishmaniasis occurs mainly at an altitude of not less than 2000 feet (about 609.6m), with an average annual relative humidity of not less than 70%, and temperatures between 7.2 and 37.2. tropical and subtropical areas. The climate and vegetation in these areas are suitable for the propagation of Leishmania vector.

Leishmaniac clinical manifestations

Incubation period

According to domestic observations, it takes approximately 4 to 6 months for infants born during the season of white peony to show clinical symptoms. However, the length of the incubation period for Leishmaniasis is also affected by factors such as the patient's immunity, nutritional level, and the number of protozoal infections, which can lengthen or shorten it.

2. Early symptoms

Most symptoms of Leishmaniasis occur gradually. In the beginning, there is usually irregular fever, and the spleen is enlarged with cough and diarrhea. Fear and insomnia are also common symptoms of early Leishmaniasis. In addition to fever and diarrhea, infants and young children may also have night crying, irritability and other symptoms. Menorrhagia or atresia is often an early symptom of women's patients.

3. Major symptoms

The clinical symptoms of patients become increasingly obvious 2 to 3 months after the onset of symptoms. The main performances are as follows:

(1) Fever Fever is the main symptom of Leishmaniasis, accounting for about 95% of cases. The heat pattern of Leishmaniasis is very irregular, with irregular rises and falls, sometimes continuous, sometimes intermittent or relaxation, and sometimes two rises and falls in a day, called bimodal fever, which is more common in the early stages. Patients usually have fever in the afternoon, and they feel tired when they get fever. When the fever rises above 39 ° C, they may be accompanied by chills and headaches, but there are no symptoms of faint slang, and night sweats are common.

(2) Splenomegaly Splenomegaly is the main sign of Leishmaniasis, which can usually be touched half a month after the first fever, and the lower end of the splenomegaly may reach the umbilicus in 2 to 3 months, 6 months It may extend beyond the umbilicus, the largest reaching above the pubic bone. The enlarged spleen is soft in the early stages of the disease and harder in the later stages. The surface of the spleen is generally smooth without tenderness.

(3) About half of the patients with hepatomegaly have enlarged liver. Hepatomegaly often appears later than the splenomegaly, and the degree of swelling is not as obvious as that of the splenomegaly, and rarely exceeds 6cm below the right costal margin.

(4) Patients with gastrointestinal symptoms often have stomatitis. In addition to ulcers on the mucous membranes, the gums are often rotten and easy to bleed. Patients with loss of appetite, often feel indigestion and stomach fullness after eating, can even cause nausea, vomiting and abdominal pain.

(5) The pulse rate of patients with circulatory symptoms mostly increases, and blood pressure often decreases due to anemia and adrenal dysfunction. Oedema can occur due to a decrease in the patient's total plasma protein and anemia. Edema is most common in the lower limbs and face. Occasionally, systemic edema may occur. In advanced patients, edema may be more pronounced due to liver damage, and the prognosis is more serious. The occurrence of epistaxis and gingival bleeding is mainly due to a large decrease in platelets of patients. Most of epistaxis occur during fever, most of which come suddenly, ranging from a few drops to as long as several hours, which can usually stop.

(6) Lymph nodes in patients with other symptoms often have mild or moderate swelling, especially in the neck and groin areas. Cough at night is one of the common symptoms of Leishmaniasis, and it is more severe. The overwhelming majority of women suffer from menstruation after Leishmaniasis, which affects their fertility.

Leishmaniasis can be relieved during the course of the disease. The temperature is normal for a period of time, the appetite increases, and the enlarged spleen also shrinks slightly. However, after a period of time, fever and spleen continue to increase. Such repeated attacks, the condition is getting worse, and in the late stage of the disease, there is no remission. Most of the patients in the advanced stage are thin, with a lack of energy, thin and dull hair, dry skin, pale skin, and hyperpigmentation in the frontal, temporal, and around the mouth. The abdomen is often prominent due to hepatosplenomegaly, and the limbs appear thinner. Children's development is hindered after getting sick.

(7) Red blood cells, white blood cells, and thrombocytopenia in patients with changes in blood image are related to hypersplenism. Leukocytes begin to decrease early in the disease, and become more pronounced as the course of the disease progresses. The decrease in leukocytes is mainly caused by the decrease of neutral polymorphonuclear leukocytes, large mononuclear cells are generally normal, and eosinophils and basophils are also reduced, so the proportion of lymphocytes is relatively increased.

Patients' red blood cells and hemoglobin were significantly reduced. Reduced platelet count. Due to the patient's anemia and an increase in gamma globulin and fibrinogen, the rate of red blood cell sedimentation is accelerated.

(8) Changes in liver function Due to liver dysfunction and massive proliferation of plasma cells in the liver and spleen, patients with Leishman disease cause a large increase in globulin and a decrease in albumin. The ratio of white and globulin is approximately 1: 1.7. Contrary to normal people. In patients with a longer course, liver cells are damaged, especially in advanced patients. Therefore, various liver function tests have a strong positive response.

Leishmaniasis

Etiological examination

(1) A small amount of bone marrow is extracted by puncture of the sacrum, made into a smear, and examined by microscopy after staining. The detection rate of Leishmania in this method is about 85%. The detection rate of patients with Leishmaniasis infected with HIV can reach 98%.

(2) The spleen is punctured to aspirate the spleen. After the needle is pulled out, the spleen in the needle is injected on a glass slide to make a smear and stained for microscopy. The protozoan detection rate of splenic puncture is very high, which can reach about 95%.

(3) The lymph node puncture lymph fluid was used to make smears and stained for microscopy. For newly diagnosed patients, the detection rate of protozoa is generally about 50%, but for patients with Leishmaniasis combined with HIV infection, the detection rate can reach 100%.

(4) Examination of the skin with a smear after making a smear. In the case of PKDL, Leishmania can usually be detected.

(5) Protozoa culture Under strict aseptic operation, various tissue fluids obtained from bone, spleen, lymph nodes or skin lesions of suspicious patients are placed in Sanen medium and cultured in a 22-240C incubator. After 15 days, take a small amount of culture fluid with platinum ears on a glass slide and inspect it under a light microscope (high magnification). If the pre-flagellate body of Leishmania is found, the diagnosis can be confirmed.

2. Serological examination

New technology for immunological diagnosis of Leishmaniasis can be used to detect circulating antibodies, circulating antigens, and circulating immune complexes in infected hosts. It plays an important role in assisting pathogen diagnosis and judging the epidemic situation. Currently, there are two main categories of antibody detection and antigen detection. Among them, the following three techniques are used to detect antibodies.

(1) Immunofluorescence assay (IFAT) The positive rate of IFAT test for Leishmaniasis is 100%, the lowest antibody titer is 1: 320, the highest is 1: 5120, cross-reaction with healthy people and other diseases, antibody titer No more than 1:20.

(2) Enzyme-linked immunosorbent assay (ELISA) and dot-enzyme-linked immunosorbent assay (Dot-ELISA ) can be judged as positive if they are greater than or equal to the negative control OD mean (x) plus 3 standard deviations (SD), Leish The coincidence rate of Mann's disease ELISA and pathogen detection was 100%. It is worth noting that there is a 23% cross-reaction with leprosy.

Dot-ELISA is a simple, sensitive and specific detection method developed on the basis of ELISA. The observation results are based on the presence or absence of spots, which can be visually inspected, and are not limited by the spectrophotometer reading. And records can be kept for a long time. The serum of patients with Leishmaniasis can have blue spots at a dilution of 1: 100 to 1: 800, and the coincidence rate with positive pathogen detection is 97.6%. No cross-reactions with malaria, pulmonary fluke, leprosy and other diseases.

(3) During the detection of immunochromatographic diagnostic test strip (ICT) , take a drop (about 20-30 l) of whole blood or serum from a patient with Leishmaniasis on a sample pad, and perform chromatography and antigen-association within 3 to 5 minutes. Combined positive bands can be visually inspected. This method is fast and sensitive, and the compliance rate with pathogen detection can reach 100%.

Detection of circulating antigens in Leishmaniasis can not only indicate active infection of the host, but also reflect the degree of infection and be used for efficacy evaluation. There are three common techniques.

1) Enzyme-labeled monoclonal antibody dot-ELISA direct method: This method detects the corresponding CAg in the serum of patients with leishmaniasis, and the positive rate is 90.6%. The direct method experiment is simple and convenient, the whole process is 4 hours. The monoclonal antibody-antigen spot test (McAb-AST) is also used to detect circulating antigens for Leishmaniasis, with a positive detection rate of 97%. Both methods can be used to evaluate the efficacy of Leishmaniasis.

2) Monoclonal Antibody-Enzyme-linked Immunostaining Technique (McAb-EITB).

3) SandwichDot-ELISA for double antibody sandwich dot-ELISA.

Leishmaniasis diagnosis

1. Diagnostic criteria for Leishmaniasis

(1) Residents of endemic areas of Leishmaniasis, or persons who have lived in the endemic area during the season of Baiji (May to September).

(2) Long-term irregular fever, progressive enlargement of the spleen, mild or moderate enlargement of the liver, decreased white blood cell count, anemia, thrombocytopenia, or symptoms of epistaxis and gum bleeding; the course of disease is generally within 2 years .

(3) Detection of positive antibodies by indirect fluorescent antibody test, enzyme-linked immunosorbent test or ICT test strip, or detection cycle using monoclonal antibody dot-ELISA or monoclonal antibody-antigen dot test (McAb-AST method) Antigen was positive.

(4) On the smear of bone marrow, spleen or lymph node, smears of Leishmania are found or the puncture is injected into Sanen medium to cultivate the pre-flagellate.

Suspected cases: 1 and 2 cases.

Clinical diagnosis: suspected case plus Article 3.

Confirmed cases: suspected cases plus Article 4.

2. Diagnostic criteria for cutaneous leishmaniasis (PKDL)

(1) Most cases have a history of Leishmania several years or more than ten years ago, and they can also occur in the course of Leishmania. A few patients have no history of Leishmania and are primary cases.

(2) There are subcutaneous nodules, pimples or fading spots on the face, limbs or trunk. The white blood cell count is within the normal range. Eosinophils are usually above 5%.

(3) McAbdot-ELISA was positive for circulating antigen.

(4) On the smear of tissue fluid or skin tissue scrape drawn from the nodule and pimples, the non-flagellate body of Leishmania was found or the skin tissue was cultured in Sanen medium and the pre-flagellate body was found.

Suspected cases: 1 or 2 cases.

Clinical diagnosis: suspected case plus Article 3.

Confirmed cases: suspected cases plus Article 4.

3. Diagnostic criteria for lymph node leishmaniasis

(1) Patients mostly occur in adults who have lived in non-endemic areas and entered Leishmaniasis areas (mountains, deserts) in infants and young children, mainly from infants and young children.

(2) One or more lymph nodes in the groin, thigh, neck, underarms, behind the ears, supraclavicular and popliteal sockets are swollen as large as peanuts or soybeans, or walnuts are formed by the fusion of several enlarged lymph nodes A lump of the same size.

(3) Aspirate the tissue fluid smear from the enlarged lymph nodes or check the Leachmania non-flagellate body from the tissue section of the removed lymph node, or culture the lymph node tissue in Sanen medium to find the pre-flagellate body.

Suspected cases: 1 or 2 cases.

Confirmed cases: Suspected cases plus Article 3. The flagellum of Leishmania seen under an optical microscope (oil microscope) was circular, with an average size of 4.4 m × 2.8 m. After Giemsa or Wright staining, the cytoplasm of the protozoa is light blue; the position of the nucleus is often close to the cell membrane and stained red; the moving substrate is rod-shaped, located on the opposite side of the nucleus, and is purple-red; sometimes visible near the moving substrate Small vacuoles. The promastigotes in the San'en medium or the white pupa digestive tract are spindle-shaped, and the cytoplasm is light blue after staining. The crimson nuclei are generally located in the middle of the insect body, and the moving matrix is at the front of the nucleus, which is purple-red. The matrix is located in The foremost part of the worm body is red granules, and the flagella are thus emitted and extended to the outside as a tool for exercise.

Differential diagnosis of Leishmaniasis

Leishmaniasis should be differentially diagnosed with the following diseases.

Leukemia

Patients with chronic myeloid leukemia and chronic lymphocytic leukemia are mostly adults with symptoms such as splenomegaly, anemia, and epistaxis and bleeding from the gums, much like Leishmaniasis, which can be identified by routine blood tests.

2. Capsular histoplasmosis

The pathogen is capsular histoplasma, which has been found in Hubei, Sichuan, Guangxi, Zhejiang, Jiangsu, and Yunnan provinces in China in recent years. Patients with disseminated capsular histoplasmosis have enlarged liver and spleen, anemia, and decreased white blood cells and thrombocytosis. Pathogens seen in patients with bone marrow, spleen, or lymph node extracts are also easily confused with Leishmania Every misdiagnosis is Leishmaniasis. However, the internal structure of the pathogen is different from that of Leishmania, and the structure of the moving matrix is not visible; the patient's ICT test is negative, and the diagnosis can be confirmed by histoplasmin and intradermal test and fungal culture.

3. Bantes syndrome

The course of the disease can be divided into three stages, with only anemia and spleen in the early stage, liver and spleen enlarged in the middle stage, and symptoms of nausea and diarrhea, and symptoms of liver cirrhosis such as vomiting blood, ascites, weight loss, and chest and abdomen in the later stage The veins are swollen. Patients are mostly adults, and infants and young children are rare. Except for other diseases or advanced stages, the patient is generally in good condition, normal appetite, no other discomforts such as fever, the increase in globulin is not significant, the course of disease is very long, and it may last 10 to 20 years. Identification.

Skin-type Leishmaniasis should be distinguished from neoplastic leprosy. A skin scraping test looking for antacids and Leishmania can confirm the diagnosis.

Skin-type Leishmaniasis should also be distinguished from cutaneous Leishmaniasis. Skin Leishmaniasis in the Old World is a simple skin lesion caused by several skin-prone Leishmania infections. The patient has no history of Leishmaniasis. Skin lesions can develop ulcers during development. Most patients have a short course of disease, and most of the ulcers heal on their own in about a year. The skin lesions of cutaneous Leishmaniasis do not cause ulcers, and the course is quite long. Without treatment, the skin lesions will not disappear by themselves.

Leishmaniasis Treatment

1. Treatment for Leishmaniasis

(1) Six-day therapy with antimony stigmatol and three-week therapy with antimony stigmatol.

(2) In the case of uncured patients who were re-examined half a month after treatment with antimony stigmatol, if the body temperature was still higher than normal, the white blood cell count did not increase, the splenomegaly remained, and the protozoa did not disappear, the treatment should be considered ineffective. The dose of stigmatol can be increased, which is 1/3 more than the original dose. The second course of treatment is 8 days and 8 needles.

(3) The temperature of Leishmaniasis patients has returned to normal after treatment, and the general conditions and blood signs have improved. Splenomegaly has also been reduced. Leachmania can not be detected by puncture examination, but after a few months (generally in (Within 6 months) The body temperature rises, the spleen enlarges, and the protozoan is found on the bone marrow or splenic puncture smear, which is a relapse, which can still be treated with antimony black, and it should be increased by 1/3 based on the original dose.

(4) Anti-antimony patients Patients who have not recovered after more than three courses of antimony are clinically referred to as anti-antimony Leishmaniasis patients. The following three drugs can be used for treatment. Pentane tincture; Hydroxy stilbene; Amphotericin B.

2. Treatment of cutaneous leishmaniasis (PKDL)

The antimony stigmatosis treatment was performed on the 6th or 8th for 2 to 3 consecutive courses. Pentanepyrazine has excellent curative effect and can usually be cured. If skin damage has not completely disappeared, another course of treatment can be given.

3. The treatment of lymph node leishmaniasis

The dose and course of stibnique are the same as those for patients with Leishmaniasis.

Symptomatic treatment and management of complications:

(1) If patients with anemia have moderate anemia, iron should be given during treatment. Severe anemia, in addition to iron, can be given a small number of blood transfusions, after the anemia has improved, and then treated with antimony.

(2) Nasal bleeding First wash the nasal cavity to find the bleeding point, and then dip the cotton with 1: 1000 epinephrine solution and 3% ephedrine to place the bleeding place, or cover the bleeding site with gelatin sponge.

In addition, patients should stay in bed during treatment to prevent colds and be given nutrient-rich or high-calorie foods such as eggs, pork liver, and tofu. A sufficient amount of multivitamins are taken orally daily to facilitate recovery.

4. There are three common complications that need to be dealt with

(1) Patients with Leishmaniasis complicated by pneumonia should not be treated with antimony or pentane tincture and hydroxystilbene. If pneumonia occurs during the treatment of Leishmaniasis, the injection should be stopped immediately, treated with antibiotics, and treated with anti-Leishmaniac medicine after the symptoms of pneumonia disappear.

(2) Zoumao should be given anti-leishmaniasis treatment according to conventional methods, and timely use antibiotics.

(3) Acute agranulocytosis should be treated immediately with penicillin to prevent secondary infection. If it occurs in the course of antimony treatment, the injection of antimony should be stopped and anti-leishmaniasis treatment should be given after the symptoms disappear. But sometimes Leishmaniasis can also cause this disease, which has nothing to do with the use of antimony agents. In this case, the use of antimony agents is not only harmless, but can also promote the recovery of granulocytes with the improvement of Leishmaniasis.

Leishmaniasis prevention

1. eliminate sick dogs

In hilly or loess plateau areas of Leishmaniasis, it is advisable to use pathogen testing or serological methods to detect and kill dogs in a timely manner. In areas with a lot of sick dogs, the people should be mobilized to raise or not raise dogs.

2. Elimination and prevention

After seeing the patient during the season, the insects can be sprayed on the patient's house and the houses and barns within a radius of 15m around it to annihilate the white-chest that stays indoors or invades the room and invades the room. The use of mosquito nets is recommended, and 2.5% deltamethrin (15 mg of pure product per m of surface) is used to soak the mosquito nets once during the season of pupae. Do not sleep, it is advisable to install a perforated screen door screen with soaked deltamethrin (same as above).

In the Leishmaniasis area of the hills and the Loess Plateau, you can use 2.5% deltamethrin bath or spray dogs (2 to 3 grams per dog) to kill or Repel the white crickets that came to sting and suck blood. At night in the desert, field duty personnel should apply repellent to exposed parts of the body to prevent stings of white sturgeon.